The present invention relates to a turbomolecular pump for exhausting a gas by an interaction between a rotor and a stator and/or by an action of threaded rotor rotating at a high speed.
A general construction of a conventional turbomolecular pump is illustrated in FIG. 4. The turbomolecular pump comprises a rotor R including a main shaft 10 and a rotary cylinder 12 rotating integrally therewith, a stator S including a fixed cylinder 14 surrounding the shaft 10, and a cylindrical casing 16 surrounding the rotary cylinder 12, which are assembled on a base B. A conductance adjusting valve 100 and a gate valve 110 are provided between the pump and an apparatus A to be evacuated in the upstream of the turbomolecular pump.
In the conventional turbomolecular pump as described above, however, driving mechanisms 101, 102 for the individual valve units are provided in the proximity of the valves near the turbomolecular pump. This has posed a problem of scaling-up of the valve units, resulting in a larger overall structure of the turbomolecular pump including the valves.